<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script type="text/javascript">
			//题目描述感觉都有问题
			var solution = function(isBadVersion) {
			    return function(n) {
			        let left = 1, right = n;
			        while (left < right) { // 循环直至区间左右端点相同
			            const mid = Math.floor(left + (right - left) / 2); // 防止计算时溢出
			            if (isBadVersion(mid)) {
			                right = mid; // 答案在区间 [left, mid] 中
			            } else {
			                left = mid + 1; // 答案在区间 [mid+1, right] 中
			            }
			        }
			        // 此时有 left == right，区间缩为一个点，即为答案
			        return left;
			    };
			};
		</script>
	</body>
</html>
